Chapter 5 Transmission Planning and System Analysis

Transcription

1 Chapter 5 Transmission Planning and System Analysis In this chapter, various types of system analysis (power flow analysis, stability analysis, short circuit analysis, frequency analysis) are used and optimal transmission plans are developed to achieve the development of power stations. Short-term transmission planning (approximately until 2007) is studied to verify the PLN transmission plan and to evaluate generation constraints caused by the transmission limit of the 500kV trunk lines for stability. Mid- and long-term transmission plans for 2010 (approximately 25,000MW) and for 2015 (approximately 35,000MW) are studied in order to cope with the power development until approximately The study accounts for the various distribution patterns for the new power stations (balanced development, development mainly in West Java, development mainly in East Java, development heavily in East Java). 5.1 Current State of the Java Bali System Java is a long and narrow island, and the length from east to west is almost 1,000km and so power must be transmitted over a long distance. To cope with this problem, a 500kV transmission system was introduced in 1984 and has since been expanded. In 1999, northern 500kV transmission lines, which consist of two circuits, were completed from the Suralaya Power Station in West Java to the Paiton Power Station in East Java. As shown in Table 5.1.1, demand in West Java is high because of the high demand at Jakarta, which is located in this region. However, some of the large power stations, such as Paiton and Gresik, are located in East Java. Thus a lot of power flows from east to west through 500kV transmission lines, and power transmission is being restricted by stability considerations. To remove this restriction, southern 500kV transmission lines are being constructed. The section from the Paiton Power Station to the existing Klaten substation in central Java will be completed in 2003, and the section from the Klaten substation to the new DepokIII substation in south Jakarta will be completed in The one circuit of the transmission lines from Paiton to Klaten has already been in operation since April 2002, by bypassing the delayed Kediri substation. Figure shows the Java Bali 500kV system in Table Demand and supply balance of each area in the Java Bali system (2001) West Java Central Java East Java (Area1, 2) (Area3) (Area4) Total Demand (MW) 7,811 (60%) 2,057 (16%) 3,173 (24%) 13,041 (100%) Supply (MW) 9,848 (53%) 1,755 (9%) 7,005 (38%) 18,608 (100%) 5-1

2 5.2 Transmission Planning (Short-term) Programs and Conditions for System Analysis (1) Programs The following programs are used for system analysis. Power Flow analysis L method (Newton-Raphson method) (by Central Research Institute of Electric Power Industry) Transient Stability analysis Y method (by Central Research Institute of Electric Power Industry) Short Circuit Capacity analysis Program developed by CEPCO (2) Conditions The following are the conditions for system analysis. Fault 3LG-O (3 phase ground fault: Criteria of P3B) Fault Clearing time 100ms(500kV), 150ms(150kV) Demand Peak (Case 1) Simulated Generators 500kV system: All power stations 150kV system: Large scale thermal power stations (Muara Karang, Tanjung Priok, Tambak Rolok, Gresik, Grati) Parameters of Transmission lines and transformers P3B data or manufacturer data (Partly standard data) Generator data P3B data or manufacturer data (Partly standard data) AVR Standard data (Thyristor-type, Self-excitation) Governor Standard data PSS Not included Results (1) Transmission of the power stations in East Java and Tanjung Jati B At present transmission of power generated by power stations in East Java, such as Paiton, is restricted due to stability problems. System stability is studied every year up until the southern 500kV transmission lines are completed. Stability is also studied for the Tanjung Jati B Power Station, which is expected to be completed in The case in which there is a delay in completing the southern 500kV transmission lines is also studied. Figure shows the results of the system analysis. 5-2

3 Figure The results of transient stability analysis In 2002: No southern 500kV transmission lines Saguling Bandung Selatan Cirebon Ungaran Klaten Grati Krian Limit 1,500MW Gresik Paiton In 2004: Operation of entire southern 500kV Saguling Depok Bandung Selatan Cirebon No restriction Ungaran transmission lines Grati Krian Gresik Paiton Tasikmalaya Klaten Kediri In 2002: Operation of one circuit between Paiton and Klaten In 2005: Operation of Tanjung Jati B Saguling Bandung Selatan Cirebon Limit 1,300MW Ungaran Gresik Krian Grati Paiton Saguling Bandung Selatan Cirebon No restriction Tanjung Jati B Gresik Krian Ungaran Paiton Grati Klaten One circuit in operation Depok Tasikmalaya Klaten Kediri In 2003: Operation of two circuits between Paiton Saguling Bandung Selatan Cirebon Limit 1,300MW Klaten Ungaran Kediri S/S in operation Kediri Grati and Klaten Krian Gresik Paiton Two circuits in operation In 2005: Delay of southern 500kV transmission Saguling Bandung Selatan lines and operation of Tanjung Jati B Cirebon Limit 1,3001,800MW Tanjung Jati B Ungaran Grati Krian Gresik Paiton In 2003: After double ð connection at Cirebon Klaten Kediri Saguling Bandung Selatan Cirebon Single ð connection Double ð connection Ungaran Gresik Krian Grati Paiton Limit 1,300MW 1,400MW Klaten Kediri 5-3

4 (2) Transmission planning for repowering at the Muara Karang Power Station Transmission planning is studied for the Muara Karang Power Station (existing capacity: 1209MW) in northern Jakarta, where repowering (capacity increase: 420MW) is expected in 2006 and Even though the power flow through the 150kV transmission lines between Muara Karang and Duri Kosambi (two routes), and between Duri Kosambi and Petukangan will be great at peak load, generation at the Muara Karang Power Station will not need to be restricted even when there is a fault with one circuit of the transmission lines. However, during off-peak periods (the load is 70% of the peak load) generation at the Muara Karang Power Station will need to be restricted when there is a fault with one circuit of the transmission lines (see Figure and Table 5.2.1). (It has to be recognized that the amount of restriction depends largely on the demand forecast for that area. The demands of the substations for power flow analysis are forecasted based on the power flow diagram in "PENGUSAHAAN SISTEM JAWA BALI 2001" and the demand forecast for the entire Java Bali system (Case 1).) The following measures can be considered for removing this restriction. (A) Reinforcement of the existing 150kV transmission lines between Muara Karang and Duri Kosambi (2 routes), and between Duri Kosambi and Petukangan by reconductoring to sag suppression electric conductors (such as thermo-resistant ACSR, gap-type ACSR and extra thermo-resistant aluminum alloy conductor galvanized invar-reinforced series). (Economical comparisons should be studied in detail to select the best type of sag suppression electric conductors.) (B) Expansion of the 150kV system to increase the demand that is directly supplied from Muara Karang and Duri Kosambi along with the demand increase in Jakarta city. (A) would be a drastic measure. (B) would be an efficient measure, if it were also used as a measure against the demand increase in Jakarta city. It is difficult to remove the entire restriction during off-peak only with (B). Therefore, it is more desirable to adopt (A) as a drastic measure. However, in light of the following items, consideration should be given to reducing the amount of generation restriction with (B), and to cope with N-1 contingency by operational spinning reserve. - There will be no restrictions at peak load, and no restrictions during off-peak without contingency. - It will be possible to reduce generation at Muara Karang during off-peak periods, because it is a power station intended for middle and peak loads. 5-4

5 - The amounts of generation restrictions will decrease if periodic inspections and repairs are taken into consideration. - The amounts of generation restrictions will decrease in accordance with the demand increase in the area. The results of the stability analysis show that there will be no problems after the Muara Karang repowering. However, the stability will be severe in case of a transmission line fault between Muara Karang and Duri Kosambi, so loop operation between Tangerang and Jatake could be possible to improve stability. After repowering of the Mura Karang Power Station, the situation will be very severe in the Gandul 150kV subsystem in terms of short circuit capacity. Therefore, a split operation of the 150kV system and upgrading of the facilities will be needed. 41 Tangerang Jatake Figure Normal condition (Off-peak in 2007) MuaraKarang (Unit:MW) PLTG PLTU Repowering Addition of 420MW Cengkareng 159 DuriKosambi Balaraja kV Kembangan 500kV CitraHabitat Legok Lengkong Serpong Cikupa Table Power flow in normal condition and with N-1 contingency (Off-peak in 2007) Contingency Power Restriction Transmission Capacity Availability flow of generation lines (MVA) Factor (MW) (MW) M.K. PLTU-D.Kosambi 810 (2405) % 0 Normal M.K. PLTGU-D.Kosambi 810 (2405) % 0 D.Kosambi-Petukangan 810 (2405) % 0 M.K. PLTU M.K. PLTU-D.Kosambi 405 (1405) % 46 -D.Kosambi M.K. PLTGU-D.Kosambi 810 (2405) % 101 1cct-fault D.Kosambi-Petukangan 810 (2405) % 0 M.K. PLTGU M.K. PLTU-D.Kosambi 810 (2405) % 59 -D.Kosambi M.K. PLTGU-D.Kosambi 405 (1405) % 130 1cct-fault D.Kosambi-Petukangan 810 (2405) % 0 D.Kosambi M.K. PLTU-D.Kosambi 810 (2405) % 0 -Petukangan M.K. PLTGU-D.Kosambi 810 (2405) % 0 1cct-fault D.Kosambi-Petukangan 405 (1405) % *1: Calculated on the assumption that the power factor is 95%. 158 Angke 183 KebonJeruk Gandul BudiKemuliaan 133 Senayan Petukangan kV 500kV

6 (3) Transmission planning for Muara Tawar Power Station Transmission planning is studied for the Muara Tawar Power Station (existing capacity : 920MW) near Jakarta, where the expansion of Block (370MW) or the extension of Block (750MW) is expected in 2006 and ) Expansion of Block Figure shows the expected power flow diagram at peak load in 2007 after expansion of Block (370MW). The power flow of each transmission line will be within the thermal capacity of one circuit, therefore there will be no overload even when there is a fault with one circuit. There will also be no problems in regard to stability. Figure Expansion of Block (Peak in 2007) (Unit:MW) Cawang 486 Bekasi 2) Extension of Block 381 Muara Tawar Cibinon Figure shows the expected power flow diagram at peak load in 2007 after extension of Block (750MW). The power flow of each transmission line will be within the thermal capacity of one circuit, therefore there will be no overload even when there is a fault with one circuit. There will also be no problems in regard to about stability Tambun Cibatu Figure Extension of Block (Peak in 2007) (Unit:MW) Muara Tawar Expansion of Block (370MW) 628 Cirata 969 Saguling 500kV 4xDOVE 2cct 1715MVA/cct Extension of Block (750MW) Cawang 486 Bekasi Cibatu kV 4xDOVE 2cct 1715MVA/cct 1271 Tambun Cibinon Cirata 1335 Saguling

7 (4) Short circuit capacity Figure shows the result of a short circuit analysis in the 500kV Java Bali system in There will be no problem in terms of with short circuit capacity in the 500kV system. Suralaya Cilegon Kembangan Balaraja Gandul Cawang Depok 28 Figure Short Circuit Current (2007) 18 Cibinong Bekasi Tambun Saguling Muara Tawar Cibatu Cirata Bandung Selatan Cirebon Ungaran Tanjung Jati B Ngimbang (Unit:kA) Gresik Krian Surabaya 16 Selatan Paiton 26 Grati (5) Frequency Tasikmalaya Rawalo Klaten Kediri By increasing the unit capacity of the generators, the benefit of economies of scale increases. But the larger the unit capacity of a generator becomes, the larger the drop in frequency and the amount of load shedding will be in the case of a generator failure. At present, the largest unit in the Java Bali system is 615MW at Paiton. In 2005 the largest will be 660MW with the operation of Tanjung Jati B. Through the least squares method and using the data of "EVALUASI OPERASI SISTEM TENAGA LISTRIK JAWA BALI 2000", the relation between the rate of generation loss (=(generation loss) /(system capacity)) and the drop of frequency in the Java Bali system is as follows: f = x P Table shows the frequency drop that is calculated by this equation when the largest generator parallels out. It shows the amount of load shedding necessary for the frequency to recover to 49.5Hz. Table Frequency drop and load shedding (Case1) Peak Minimum Peak Minimum Load (MW) 12,231 3,936(32%) 16,185 5,179(32%) Largest Unit (MW) 615(Paiton) 660(Tanjung Jati B) Frequency Drop (Hz) Load shedding (MW)

8 5.2.3 Conclusions and Recommendations (1) Removal of transmission restrictions in East Java 1) Completion of southern 500kV transmission lines The entire southern 500kV transmission lines have to be completed to remove all the transmission restriction caused by system stability in East Java. Theses lines should be constructed as soon as possible. The land acquisition problems near the Depok III substation should be solved as soon as possible in order to complete the entire southern 500kV transmission lines in If the land acquisition problems are not solved, a temporary connection of the southern 500kV transmission line to the northern 500kV transmission line near Bandung Selaten or near Upper Cisokan should be studied. 2) Double connection at Crebon substation After completion of the section from Paiton to Klaten, the power flow between Ungaran and Cirebon will be restricted by stability considerations. Therefore, the connection of the 500kV transmission line at the Cirebon substation should be changed from a single configuration to a double configuration to alleviate the transmission restrictions. (2) Transmission planning for Tanjung Jati B Power Station To stably transmit the power of the Tanjung Jati B Power Station, construction of a new transmission line between Tanjung Jati B and Ungaran will be needed. The entire southern 500kV transmission lines have to be completed to remove the generation restriction caused by stability considerations at the Tanjung Jati B Power Station. Therefore, the entire southern 500kV transmission lines should be constructed in (3) Transmission planning for repowering at Muara Karang Power Station After repowering of the Muara Karang Power Station, its generation will be restricted when there is a fault with one circuit of the transmission lines. To remove this restriction, it is desirable to reinforce the existing 150kV transmission lines between Muara Karang and Duri Kosambi (two routes), and between Duri Kosambi and Petukangan by reconductoring to sag suppression electric conductors (such as thermo-resistant ACSR, gap-type ACSR and extra thermo-resistant aluminum alloy conductor galvanized invar-reinforced series). However, considerations should be given to expanding the 150kV system in order to increase the demand that is directly supplied from Muara Karang and Duri Kosambi in accordance with the demand increase in Jakarta city. Therefore, this alternative should be studied in detail, including demand forecast for this area. 5-8

9 With respect to short circuit capacity, after the repowering of the Muara Karang Power Station, the situation will be very severe in the Gandul 150kV subsystem. Therefore, a split operation of the 150kV system and upgrading of the facilities will be needed. (4) Transmission planning for Muara Tawar Power Station With respect to the expansion of Block (370MW) and the extension of Block (750MW) at the Muara Tawar power station, the power can be transmitted by the existing 500kV transmission lines with N-1 contingency as long as one of the plans is carried out. (5) Improvement of system stability 1) Using PSSs At present, the PSSs (Power System Stabilizer) are not used at some power stations. Therefore, the PSSs should be adjusted and used to improve stability. 2) Adoption of differential relay for trunk lines At present, two sets of distance relays are adopted to protect each 500kV transmission line in the Java Bali system. Single-phase reclosing by using PLC (Power Line Carrier) has also been adopted. Distance relays have been technically established and their reliability is relatively high and so it is used in many countries. Recently, optical fiber communications have been introduced in the Java Bali system, and so differential relays should be introduced to protect trunk lines in the future. Differential relays have high reliability, and the fault clearing time can be shortened and multi-phase reclosing can be achieved by utilizing differential relays. In this manner stability can be improved. (6) Largest generator unit in relation to system capacity At present, the largest generator unit in the Java Bali system is 615MW at the Paiton Power Station. It is relatively large in comparison with the system capacity (13,041MW in 2001). Therefore, if a fault occurs at the largest generator, the frequency drops sharply and load shedding is needed. There are plans to install two 660MW units at the Tanjung Jati B Power Station in If a larger capacity unit is installed, the amount of load shedding will increase. Thus, installation of a larger unit has to be carefully considered. 5-9

10 (7) Margin of the transmission stability limit In this stability analysis, standard data are used for the generators. A 3-phase ground fault of one circuit is adopted, but generally a 1-phase ground fault for two circuits are stricter fault. Only the peak-load is studied, and not off-peak load or minimum load. Therefore, a sufficient transmission stability margin should be kept for system operations. 5.3 Transmission Planning (Mid- and Long-term) Demand Forecasts For transmission planning, Case 2 for which the rate of increase is larger in comparison with Case 1, was adopted. The demand for each area is as follows. Table Demand forecast (Unit: MW) Area1 Area2 Area3 Area4 Total ,495 (42%) 2,316 (18%) 2,057 (16%) 3,173 (24%) 13,041 (100%) ,077 (41%) 4,543 (19%) 3,689 (15%) 5,988 (25%) 24,297 (100%) ,413 (41%) 6,601 (19%) 5,282 (15%) 8,504 (25%) 34,800 (100%) Figure Demand forecast in each area 16,000 16,000 14,000 14,000 Peak Load (MW) 12,000 10,000 8,000 6,000 4,000 12,000 10,000 8,000 6,000 4,000 2,000 2, ,000 16,000 14,000 14,000 12,000 12,000 10,000 10,000 8,000 6,000 4,000 8,000 6,000 4,000 2,000 2,

11 5.3.2 Power Development Plan In terms of the power development plan, the Base Case (Demand-JICA/LPE Case2) was adopted for transmission planning. Table Power development plan for transmission planning Total Coal (600MW) Combined Cycle (600MW) Gas Turbine (120MW) Pumped Storage (250MW) Study Cases The years 2010 and 2015 were studied for the transmission planning. The distribution of the new power stations is assumed as follows. Table Distribution patterns for the new power stations Balance Case The power stations are developed in accordance with the demand in each area West Case The power stations are developed mainly in West Java East Case The power stations are developed mainly in East Java Heavy-East Case The power stations are developed heavily in East Java Generation Table Power development plan in each area ( ) Demand (2010) Existing (2001) New Balance Case West Case East Case Heavy-East Case (Unit: MW) Area1 Area2 Area3 Area4 Total 10,077 4,543 3,689 5,988 24,297 (41%) (19%) (15%) (25%) (100%) 7,395 2,373 1,755 7,005 18,528 (40%) (13%) (9%) (38%) (100%) 5,120 3,600 2, ,840 (43%) (31%) (21%) (5%) (100%) 8,720 1,200 1, ,840 (74%) (10%) (16%) (0%) (100%) 3,920 2,400 3,120 2,400 11,840 (33%) (20%) (27%) (20%) (100%) 2, ,720 5,400 11,840 (23%) ( 0%) (31%) (46%) (100%) Note : With respect to existing generation, reduction by repowering is considered. (Muara Karang : 80) 5-11

12 Generation Table Power development plan in each area ( ) Demand (2015) Existing (2001) New Balance Case West Case East Case Heavy-East Case (Unit: MW) Area1 Area2 Area3 Area4 Total 14,413 6,601 5,282 8,504 34,800 (41%) (19%) (15%) (25%) (100%) 7,295 2,373 1,655 6,905 18,228 (40%) (13%) ( 9%) (38%) (100%) 10,160 6,300 4,320 3,600 24,380 (41%) (26%) (18%) (15%) (100%) 13,760 5,100 4,320 1,200 24,380 (56%) (21%) (18%) (5%) (100%) 8,960 5,100 4,920 5,400 24,380 (37%) (21%) (20%) (22%) (100%) 5,360 5,100 5,520 8,400 24,380 (22%) (21%) (23%) (34%) (100%) Note: The generators that will be removed by 2015 are excluded from the existing generation (300) Conditions The conditions for the study are as follows. - Based on the N-1 rule that is adopted by PLN, transmission planning is developed to ensure that there are no interruptions in the power supply when there is a failure involving just one piece of the equipment (a failure of one circuit in the transmission line). Transmission planning is developed to accommodate stability when there is a transmission fault (3LG-O: 3-phase short circuit). - Transmission planning is studied at the peak demand. - The programs for system analysis and other conditions are the same as those used for short-term transmission planning (cf Programs and Conditions for System Analysis). - With respect to the Balance Case, the ratios of periodic repair (PR) and balance stop (BS) of the generators in each area are the same. With respect to the West Case, the ratio of PR and BS is 10% in West Java, considering the dispersion of PR and BS. With respect to the East and Heavy-East cases, the ratio of PR and BS is 10% in East Java for the same reason. 5-12

13 5.3.5 Study Results (1) Power flow diagram Figures shows the power flow diagrams for each case (Balance, West, East, and Heavy-East) for (2) Summary Table shows the summary of the results Table Summary of result. Heavy-East Case Balance West Case East Case Case (Without (With measure) measure) Generation interruption Power flow No problem No problem No problem with a transmission fault No problem Stability Stable Stable Stable Unstable Stable Short Circuit Transmission Losses 500kV Third route No problem Need for Measure No problem No problem Small Medium Large Largest No need No need No need Needed Power flow No problem No problem No problem Generation interruption with a transmission fault No problem Stability Stable Stable Stable Unstable Stable Short Circuit Transmission Losses 500kV Third route Need for Measure Need for Measure Need for Measure Need for Measure Small Medium Large Largest No need No need No need Needed 5-13

14 Figure Java-Bali System Load Flow Diagram (In 2015) Unit : MW The circles show the power stations, and the rectangles show the substations. The thick lines show the new facilities after 2005 Blue color : Over stability limit Green color : Over-load with one-circuit fault Red color : Over stability limit and over-load with one-circuit fault power flow exceed one-circuit capacity Balance case Sumatra Kembangan Cawang Bekasi A Tambun Suralaya Cibinong Balaraja Gandul 750 Depok Cilegon ST12 ST13 Area ST System split for countermeasure against short circuit capacity 504 Muara Tawar Cibatu Cirata 504 Bandung 737 Selatan 350 Saguling Upper Cisocan 660 A Tasikmalaya 1800 ST23 ST21 Area Rawalo ST Tanjung Jati B CC31 Klaten 1320 ST Gresik Ngimbang Krian Surabaya Selatan A21 Cirebon A Ungaran ST Grati Area 3 Kediri 1241 No problem on power flow and stability Area 4 Paiton Kapal ST41 West case Muara Tawar Sumatra Bekasi Tanjung Jati B Gresik Cawang Area 2 Kembangan Cibatu ST22 CC ST Area Ngimbang 660 A Tambun Cirata Krian Surabaya Bandung Selatan Suralaya Cibinong Selatan Cirebon A21 A Gandul 32 Ungaran Balaraja Saguling Upper Cisocan Grati 3925 Depok 250 Cilegon 1737 ST A22 Tasikmalaya Rawalo Paiton ST13 Area ST11 ST ST ST Klaten Area Kediri 371 Kapal System split for countermeasure against short circuit capacity No problem on power flow and stability 5-14

15 ST12 East case Sumatra Bekasi Kembangan 660 Cawang A Tambun 1459 Suralaya Cibinong Cilegon ST13 Balaraja 1387 Gandul Area Depok ST System split for countermeasure against short circuit capacity Muara Tawar Cibatu 504 Cirata 350 Saguling Upper Cisocan A Bandung Selatan Tasikmalaya 590 ST ST21 Area 2 Tanjung Jati B ST31 Gresik ST Ngimbang Krian Surabaya Selatan Cirebon 1574 A21 A Ungaran CC Grati Rawalo ST Klaten Area 3 ST Kediri 2257 Area 4 Paiton No problem on power flow and stability 1800 Kapal ST41 Heavy-east case without measure Muara Tawar Sumatra Bekasi Tanjung Jati B Gresik Kembangan Cawang ST Cibatu Area 2 CC Ngimbang Area 4 ST A11 Tambun 504 Cirata Surabaya 1764 Bandung Krian Selatan Suralaya Cibinong Selatan Cirebon A21 A Ungaran CC41 Balaraja Gandul Saguling Kapal 500 Upper 867 Grati Cisocan Depok 250 Area 3 Cilegon ST12 A22 Tasikmalaya Rawalo Paiton ST Area System split for countermeasure against short circuit capacity ST23 ST21 ST Klaten ST Kediri 1800 ST44 Problems on power flow and stability 1947 Heavy-east case with measure Muara Tawar Bekasi Area 2 ST43 Sumatra Tanjung Jati B Gresik Kembangan Cawang Cibatu ST22 CC Area Ngimbang A11 Tambun Cirata Surabaya 1454 Bandung Krian Selatan Suralaya 1073 Cibinong Selatan Cirebon 773 A Ungaran CC41 Balaraja Gandul Saguling 2077 Kapal 500 A23 Upper Grati Cisocan A41 Depok Cilegon ST A22 Tasikmalaya Rawalo Paiton ST Area 1 System split for countermeasure against short circuit capacity ST23 ST21 ST Klaten ST33 Area No problem on power flow and stability Kediri 1800 ST The third 500kV route 5-15

16 5.3.6 Conclusions and Recommendations (1) Distribution of new power stations 1) From the viewpoint of the transmission system, it is important to avoid the construction of new 500kV trunk lines and to avoid reinforcement of the existing 500kV trunk lines for power development. Furthermore, it is desirable to minimize the power flows of the 500kV trunk lines to reduce the transmission losses. Therefore, it is desirable to choose the sites of the new power stations to balance the generation with the demand in each area and to balance the power flows of the northern 500kV transmission lines with the power flows of the southern 500kV transmission lines. - In area 1 (West Java), the generation is presently in balance with demand. However, the ratio of the area's demand to the total demand of the Java-Bali system is large (40%). Therefore, power development in coordination with the demand increase is desirable. - In area 2(middle West Java), the demand exceeds the generation at present, and so it is desirable to promote more power development. - In area 3 (central Java), though the demand exceeds the generation at present, construction of Tanjung Jati B will bring generation into balance with demand. Therefore, it is desirable to develop power in accordance with the increase in demand. - In area 4 (East Java), the generation greatly exceeds demand at present, therefore it is desirable to develop power in other areas. 2) If power stations with capacities greater than 2400MW are developed in area 4 (East Java) and power stations with capacities greater than 3120MW are developed in area 3 (central Java) by around 2010, the power flows on the trunk lines will be heavy and power interruption will occur when there is a transmission fault, resulting in stability problems. Therefore, a third 500kV trunk line with a distance of almost 1,000km will be needed. If power stations with capacities greater than 5400MW are developed in area 4 (East Java) and power stations with capacities greater than 4920MW are developed in area 3 (central Java) by around 2015, a third 500kV trunk line will also be needed. Therefore, it is important to avoid the concentration of power development in East Java. If construction of a third trunk line is needed, it could be a DC transmission line. Therefore, a detail study will be needed. 5-16

17 3) If the demand and the generation are not balanced in each area, partial reinforcement of the 500kV trunk lines or partial third 500kV trunk lines or 500kV transmission lines between the northern 500kV trunk line and the southern 500kV trunk line might be needed. Therefore, it is desirable to balance the demand with the generation in each area. 4) In terms of the new transmission lines from the new power stations to the existing 500kV system, it is desirable to shorten its distance as much as possible to reduce the construction costs and transmission losses and to improve transient stability. Therefore, it is desirable to choose the new sites as close to the demand (500/150kV substation) as possible when developing new power stations. From the viewpoint of reliability, it is desirable to avoid concentration of power development at one site. (2) Short circuit capacity If power stations are developed heavily in West Java, there will be the problem of short circuits in the 500kV system. Therefore, a splitting of the system or other such measures (e.g. upgrading the equipment, current-limiting reactor) will be needed. Measures against short circuit capacity should be determined by considering reliability and costs in comparison with the split of the system and other measures. 5-17

18 Chapter 6 Rehabilitation Plan of Thermal Power Plant 6.1 Summary In this chapter, rehabilitation of the existing thermal power plants was planned. The following is the flow of the examination and summary of this chapter: (1) Survey of the current status of the facilities Operational status (year of commissioning, capacity factor, etc.), derated capacity and its reason, thermal efficiency, fuel cost per kwh, etc. were surveyed. (2) Selection of focus of rehabilitation From the survey results, it was decided to focus rehabilitation on thermal efficiency improvement of conventional steam power plants (PLTU). (3) Selection of measures to improve thermal efficiency From the result of the data and the interview during the site survey, the following items were selected as the thermal efficiency improvement measures to be examined in detail. - Cleaning of feed water heater tubes - Boiler chemical cleaning - Improving high- and intermediate-pressure turbine blades - Replacement of air preheater element and seal (4) Examination of application of the thermal efficiency improvement measures Efficiency improvement, cost, internal rate of return (IRR), net present value (NPV) and payback period were examined when the selected measures were applied to the target power plants. Table shows the results. Table Application effect of thermal efficiency improvement measures (summary) 6-1

19 6.2 Conclusion Rehabilitation should be carried out beginning with high IRR items. Therefore, rehabilitation items are prioritized as follows. 1) LP-HTR cleaning with sponge This work is simple and does not require technical experience and know-how, and the cost is very small. Therefore, this can be carried out immediately by the Indonesian side alone. The targets are the last LP-HTRs of all steam power plants. This should be carried out every 8 years along with periodical inspection of LP-HTR. 2) HP-HTR cleaning with high-pressure jet One set of high-pressure water jet equipment for common use for all power plants should be purchased first and it costs about US$140,000. And then, when the work is carried out, it costs only about US$2,000-4,000 per one HTR as the costs of transportation of the equipment, consumables such as nozzles, and labor. Because this work requires technical experience and know-how, guidance from the experts of the water jet cleaning company should be received in the early stages of the introduction (e.g. for several months in total in several power plants). The targets are the HP-HTRs of Suralaya PLTU 1-7, Tambak Lorok PLTU 3, Muara Karang PLTU 4-5, Gresik PLTU 1-4 and Paiton PLTU 1-2. This should be carried out every 4 years along with periodical inspection of HP-HTR. 3) Boiler chemical cleaning Boiler chemical cleaning should be carried out at a proper time. Therefore it is necessary to determine whether or when this should be carried out following the detailed examination by the cutout test on the evaporation tube and operational state. The targets are the all steam power plants. 4) Improvement of HP & IP turbine blades and replacement of AH element & seal IRR is not too high for the high investment cost. Especially for the improvement of HP & IP turbine blades, IRR is evaluated assuming that this improvement is carried out along with the inevitable replacement due to deterioration. Therefore it is necessary to determine whether this should be carried out following the detailed examination of the state of deterioration. In the detailed examination, manufacturers should participate to examine the applicable technology and the amount of efficiency improvement from the viewpoint of design. The targets of the detailed examination for the improvement of HP & IP turbine blades are Suralaya PLTU 1-2, Tambak Lorok PLTU 3, Muara Karang PLTU 4-5 and Gresik PLTU 1-2. The targets of the detailed examination for the replacement of AH element & seal are Muara Karang PLTU 4 and Gresik PLTU

20 Chapter 7 Environmental Measures In this chapter, an overview of the environmental regulations and measures in the thermal power plants and the proposals for promoting utilization of coals in the future are studied. The flow of examination and summary in this chapter is as follows. 7.1 Environmental Regulations and Standards The whole environmental related regulations in Indonesia are investigated and the level of restriction, especially for air pollution standards, is evaluated. Indonesia reviewed its emission standards in 2000 and tightened control by reducing the limit to 1/2 of existing level. As a result, while PM emission standard is a little lax, the SO 2 and NO 2 emission standards are nearly equal to the World Bank emission standards, so the level of restriction is same as developed countries. 7.2 Current Environmental Conditions and Countermeasures in Thermal Power Plants The current gas emission from each thermal power plant by fuel type is surveyed and the proposals for environmental improvement are evaluated. Table7.2.1 Current Environmental Conditions and Countermeasures Fuel type Current conditions Countermeasures Coal-fired (Paiton, Sularaya) Oil-fired (Muara-karang) Natural gas-fired - P M: Some plants exceed the acceptable level (due to the damage of aging electrostatic precipitator - SO 2 : Emission of SO 2 is currently close to the allowable level - NO 2, PM: Good operation condition within acceptable level. - SO 2 : Exceeding the acceptable level (due to using high sulfur contents Oil) - SO 2, NO 2, PM: Good operation condition within acceptable level. - PM: Replacement of the interior parts of electrostatic precipitator is planned. - SO 2 : Difficult to purchase higher level coal. Consideration to the level of sulfur content - SO 2 : Conversion of fuel to natural gas Reduction of sulfur in Oil Installation of desulfurization facility The conversion to natural gas is the most environmental friendly proposal for existing oil-fired power plants 7-1

21 7.3 Environmental Protection Measures to Promote Utilization of Coal in Thermal Power Plants The coal reserves by coal type is shown in Table Consumption of lower-grade sub-bituminous coal and brown coal (lignite), which are abundant in coal reserves, are expected to increase in the future because they ensure better cost performance and energy security. To ensure ecological use of these types of coal, appropriate measures should be taken. In this chapter, environmental countermeasures for utilizing various type of coal and latest clean coal technologies (CCT) which are adaptable for Indonesia are studied. Table Coal reserves (%) by coal type Type of coal Amount of deposits (%) Anthracite 0.36 Bituminous coal Sub-bituminous coal Brown coal Total (1) Measures to ensure environmental with lower-grade coal a. Use of coal with lower calorific value requires: - Construction of new coal mills in order to compensate for inadequate capacity of existing mills (for existing plants); - Reinforced coal handling equipment to accommodate the expected increase in the volume of coal (for existing plants); - Re-designed combustion equipment and ventilation system that can accommodate additional supply of fuel (for new and existing plants); and, - Installation of coal mixing equipment to blend high-calorie and low-calorie coals (for new and existing plants). b. Use of coal with high sulfur/ash content requires: - Installation/addition of desulfurizers and dust disposal equipment (electrostatic precipitator) (for new and existing plants); and, - Installation/addition of equipment to treat ash and by-product of desulfurization (for new and existing plant) (2) Clean Coal Technology (CCT) that can be promoted to Indonesia The increased use of coal for power generation in many countries has spurred innovation of diverse types of CCT technologies. The three main types of boilers that may apply to Indonesia are: supercritical boiler, brown coal (lignite) -fired boiler, and circulating fluidized bed combustion boiler. 7-2

22 Chapter 8 Institutional and Organizational Recommendation for the Optimal Electric Power Development Plan and Stable Power Supply In this chapter, the following items were studied as the institutional and organizational measures contributing to realize the optimal power development plan and to ensure stable power supply. (1) Lessons from the California Power Crisis to the power sector liberalization in Indonesia In this section, the lessons from the California Power Crisis were examined to make use of the power sector liberalization in Indonesia from the viewpoint of stable power supply. (2) System for power supply bidding with a view to power supply composition This section will introduce Japan s wholesale electricity bidding system to implement the optimal power development plan by private investment in Single Buyer System. (3) An approach to power development supporting system in line with energy policy In this section, measures to support the power development in line with energy policy were examined from the viewpoint of realization of the optimal power development plan. (4) Utilization of captive power Captive power in Indonesia can affects stable supply of electric power. Therefore the demand trend of captive and the possibility to utilize as a short-term countermeasure against power deficit were examined. (5) Utilization of Demand Side Management (DSM) In this section, DSM was examined as a measure to ensure stable supply of electric power from the demand side. (6) Financial enhancement of PLN The financial situation of PLN which affects realization of the optimal power development plan was analyzed. And the required measures for enhancement of PLN financial condition were examined. (7) Measures to promote private investment The measures for promoting private investment necessary to realize the optimal electric power development plan were examined. 8-1

23 8.1 Lessons from the California Power Crisis to the Power Sector Liberalization in Indonesia California Power Crisis California s power sector reform started in Wholesale markets worked reasonably well for the first two years (1996-8) while the initial surplus of generating capacity disappeared. Then by 2000, when the demand surged and supply capacity cannot match the demand, rolling blackouts disrupted the state economy. This shortage of electricity was accompanied by the skyrocketing of the wholesale spot prices. The immediate cause of the crisis is this mismatch of the demand and supply. The problem is said to be in the design of the wholesale market, which could not provide price signal of the users and/or the incentive for new power development to the wholesale market. Because initially the major private distribution companies were not allowed to buy outside of the spot market, they were exposed to the price volatility of the market. And the price signal of the users was not transmitted to the wholesale market due to the retail price cap system. This price volatility and the lack of interaction between the wholesale market and the retail market made market participants difficult to manage their risks Lessons for Indonesia The purposes of liberalization are clearly different between the cases of California and Indonesia. California wanted to reduce the price by introducing competitive market. Indonesia wants to increase the private participants by liberalizing the market. Also in California crisis, the main concern was the establishment and regulation of a mandatory, wholesale power market based on spot pricing. But Indonesia s case is still far away from such an option. Although there are such fundamental differences, there are also lessons to be shared. a. The California case suggests the importance of the system to ensure new supply capacity in the competitive market. In other country, this function can be complemented by various means, namely a capacity obligation on distribution company s purchasing power in market, a parallel capacity market to the energy spot market, or a forward energy trading market whose prices signal expectations about future supply/demand balances. At the same time, the market rule has to be designed so that investors in new supply capacity do not face major barriers to entry to the wholesale power market. These barriers include uncertainty and expense in facing delays to the permitting process, regulatory uncertainties. 8-2

24 b. Indonesia like other developing countries should start with limited forms of competition that can evolve to full wholesale competition. The spot market should not be the priority until the sector can manage full competition. c. Regulators should encourage and even require supplies to take measures for allowing large users to adjust their demand for power in real time, through smart metering and other means, since competition works properly only when both suppliers and users interact in the market. 8-3

25 8.2 System for Power Supply Bidding with a view to Power Supply Composition This section will introduce Japan s wholesale electricity bidding system as an example for reference in connection with power procurement under the SBS system, which has yet to be clearly defined. Under the wholesale power system, the Japanese power companies play a role relatively similar to that of the single buyer, but the way they obtain new power sources would be of reference in the design of the SBS Problems in Past Invitations to IPPs in Indonesia In 1992 Presidential Decree No.37 was promulgated as a measure to solve the power supply shortage foreseen by the Indonesian government. The decree strongly encouraged private sector participation in power source development projects. By the time of the Asian currency crisis in 1997, purchase contracts had been signed with a total of 27 IPPs. However, the economic depression which began with the Asian currency crisis led to most of the contracts being broken. Under the contracts which were not broken, the currency crisis led to a sharp drop in the value of the Rupiah, causing a severe back spread between the PLN s Rupiah-based electricity sale price and the US$-based unit prices for electricity under the contracts with IPPs (approximately 6c/kWh excess). This back spread drastically weakened the PLN s financial position, and it is now reviewing contract unit prices. The plan to bring in IPPs in Indonesia was intended to use private sector funds to augment power supply development funds, even though they cost rather more, because there was no way to develop sufficient power sources to meet the growth in power demand from public sector funds alone. In order to attract private capital while simultaneously reducing power supply costs, the IPPs were offered attractive terms, but at the same time the IPPs involved had to be chosen with consideration for a balanced power supply composition Power Source Bidding System taking Power Source Composition into account As described above, Indonesia s introduction of IPPs was intended to use private sector funds to augment power supply development funds, even though they cost rather more, because there was no way to develop sufficient power sources to meet the growth in power demand from public sector funds alone. In that sense, it differs from the nature of the Japanese IPP bidding system, which was intended to apply market principles to the power sector and reduce electricity charges. Therefore the methods of the Japanese system which appear to be applicable to the future design of the SBS will be summarized below in conclusion. 8-4

26 (1) Expansion of power sources using the power source bidding system In Indonesia s past introduction of IPPs, the majority of power sources are applied to base load, and the system of soliciting sources from IPPs was certainly advantageous for base load sources. In future, if all power sources are to be developed by the SBS bidding system under the New Electrical Power Law, a bidding system will have to be introduced with methods that allow peak and middle power sources to compete effectively with base power sources. Specifically, the power purchase prices will have to be set for the anticipated peak, middle and base power supply types (i.e. equipment usage rates) in order to encourage investment in power stations that will have lower equipment usage rates. Under such a method, there would be progress in expansion of peak and middle power sources. (2) Power supply bidding system with consideration of power source combination If peak, middle and base power sources are all targeted for investment under the power source bidding system, the volume solicited and the power purchase prices should be set for each equipment usage rate and fuel type in order to manipulate the power source combination while suppressing electricity charges. Therefore long-term targets for power source combination should be studied with a view to making effective use of primary energy and conserving the environment. It is important to clarify the direction of the nation s power source development in this way in order to provide information on which the private sector can base investment decisions. 8-5

27 8.3 An Approach to Power Development Supporting System in line with Energy Policy Under the Electric Power Policy, energy development in Indonesia is focused on reduction of use of fossil fuel to realize sustainable energy development. New and renewable energy sources are also being introduced as switches in energy use, for the sake of environmental preservation. In this section, electric power development supporting systems to introduce new and renewable energy and to introduce gas-fired power using CDM scheme are studied Introduction of New and Renewable Energy Sources We introduce, in this report, the measures for new and renewable energy promotion, which have introduced in foreign countries. 1) Obligation to purchase with fixed price 2) Obligation on the national electric power company to purchase by lump-sum bid 3) Quota and RPS (Renewable Portfolio Standard) 4) Self-regulated purchase system by the fixed price by Electric Power Companies Clearly the key point of debate in system evaluations now used by each country is how to reconcile [1] expanded introduction of these energy types with [2] reduction of their costs. The existing systems in Germany and Britain emphasize [1] with legal regulations, and have gained a grasp of the issues involved in evaluation. The US RPS system gave more consideration to [2] through the introduction of market principles, but it is still too soon to produce an evaluation. In order to identify the optimum system for Indonesia at this stage, it is important for the Indonesian government to clarify its priorities between points [1] and [2]. If it aims to expand the introduction of new and renewable energy sources in the short term, there will be an attendant fiscal burden, but legislative measures could be used to make the use of new and renewable energy sources mandatory. If it aims to reconcile expanded introduction of these energy types with cost reduction in the long term, it will have to await an evaluation of the RPS. 8-6